Wikipedia wrote:Mushishi is set in an imaginary time between the Edo and Meiji periods, featuring some 19th-century technology but with Japan still as a "closed country".[3] The story features ubiquitous creatures called Mushi (蟲?) that often display what appear as supernatural powers. It is implied that there are many more lifeforms more primitive than "normal" living things such as animals, plants, fungi and bacteria, and Mushi is the most primitive of all. Due to their ethereal nature most humans are incapable of perceiving Mushi and are oblivious to their existence, but there are a few who possess the ability to see and interact with Mushi. One such person is Ginko (ギンコ?), the main character of the series. He employs himself as a Mushi Master (蟲師 mushi-shi?), traveling from place to place to research Mushi and aid people suffering from problems caused by them.

The series is an episodic anthology in which the only common elements among episodes are Ginko and the various types of Mushi. There is no overarching plotline. The most frequently seen character is an otherworldly-looking man named Ginko, who is voiced by Yuto Nakano in the original version and by Travis Willingham in the English dub.[4][5] Ginko is a rare person who attracts mushi, which inspires a lifestyle of constant wandering. He also smokes in order to keep the mushi away. In terms of personality, Ginko is generally laid back and focused on his work. However, he can be very serious when it comes to protecting people from mushi. He also often stresses that the mushi are not evil, but merely trying to survive like everyone else. A majority of the stories do not focus on Ginko, but rely on him as a catalyst to move the story forward by diagnosing or curing mushi-related illnesses and phenomena.

Mushi is the Japanese word for bug or bugs. Shi(氏 [し] [ɕi]?), among other things, is an honorific used in formal writing, and sometimes in very formal speech, for referring to a person who is unfamiliar to the speaker, typically a person known through publications whom the speaker has never actually met.[1] There are other meanings for Shi, but in the context of this series, the honorific is most fitting. There's a live action film based on the series called Mushi-Shi: The Movie and Bugmaster[2].

MAL Rewrite wrote:"Mushi": the most basic forms of life in the world. They exist without any goals or purposes aside from simply "being." They are beyond the shackles of the words "good" and "evil." Mushi can exist in countless forms and are capable of mimicking things from the natural world such as plants, diseases, and even phenomena like rainbows.

This is, however, just a vague definition of these entities that inhabit the vibrant world of Mushishi, as to even call them a form of life would be an oversimplification. Detailed information on Mushi is scarce because the majority of humans are unaware of their existence.

So what are Mushi and why do they exist? This is the question that a "Mushi-shi," Ginko, ponders constantly. Mushi-shi are those who research Mushi in hopes of understanding their place in the world's hierarchy of life.

Ginko chases rumors of occurrences that could be tied to Mushi, all for the sake of finding an answer.

It could, after all, lead to the meaning of life itself...

If you've never watched an anime series, this one is probably a good start. There is plenty of rich symbolism and allegory in each episode and a motif inlaid into the entire series that's worth watching for. Also, this show is on the side of realism and isn't heavy with Ero/Ecchi themes like several other anime series are. This is something that anyone could enjoy. I've posting this because of a) the rich symbolism/allegory work in the episodes and b) the correlations that can be drawn between the supernatural interactions of people (living in the Material Sector) and the Mushi (who are assumed to be Cosmic Sector inhabitants/influences).